<div dir="ltr">changes in ganesha management code were made in April 2016 to reduce the need for high maxfilestocache value, the ganesha daemon adjusts it allowed file cache by reading the maxfilestocache value and then reducing its allowed NOFILE value . the code shipped with 4.2.2 release. <div>you want a high maxfilestocache value on CES nodes for various reasons. just FYI we have some customers who have MFTC set to 15 Million :-)</div><div><br></div><div>sven <div><br></div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr">On Fri, Mar 24, 2017 at 11:13 AM Bryan Banister <<a href="mailto:bbanister@jumptrading.com">bbanister@jumptrading.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg">Hi Vipul,<u class="gmail_msg"></u><u class="gmail_msg"></u></span></p>
<p class="MsoNormal gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></span></p>
<p class="MsoNormal gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg">Hmm… interesting. We have dedicated systems running CES and nothing else, so the only thing opening files on GPFS is ganesha. IBM Support recommended we massively
increase the maxFilesToCache to fix the performance issues we were having. I could try to reproduce the problem to investigate further, but the impact to users would not be appreciated.
<u class="gmail_msg"></u><u class="gmail_msg"></u></span></p>
<p class="MsoNormal gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></span></p>
<p class="MsoNormal gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg">Setting such a high value for maxFilesToCache has direct impact on the token manager so fixing this would be very good.<u class="gmail_msg"></u><u class="gmail_msg"></u></span></p>
<p class="MsoNormal gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></span></p>
<p class="MsoNormal gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg">Perhaps IBM could take a closer look at this without our involvement?<u class="gmail_msg"></u><u class="gmail_msg"></u></span></p>
<p class="MsoNormal gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg">-Bryan<u class="gmail_msg"></u><u class="gmail_msg"></u></span></p>
<p class="MsoNormal gmail_msg"><b class="gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d" class="gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></span></b></p>
<p class="MsoNormal gmail_msg"><b class="gmail_msg"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif" class="gmail_msg">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif" class="gmail_msg"> Vipul Paul [mailto:<a href="mailto:vpaul@us.ibm.com" class="gmail_msg" target="_blank">vpaul@us.ibm.com</a>]
<b class="gmail_msg">On Behalf Of </b>IBM Spectrum Scale<br class="gmail_msg">
<b class="gmail_msg">Sent:</b> Friday, March 24, 2017 12:18 PM<br class="gmail_msg">
<b class="gmail_msg">To:</b> gpfsug main discussion list <<a href="mailto:gpfsug-discuss@spectrumscale.org" class="gmail_msg" target="_blank">gpfsug-discuss@spectrumscale.org</a>>; Bryan Banister <<a href="mailto:bbanister@jumptrading.com" class="gmail_msg" target="_blank">bbanister@jumptrading.com</a>><br class="gmail_msg">
<b class="gmail_msg">Subject:</b> Re: CES node slow to respond<u class="gmail_msg"></u><u class="gmail_msg"></u></span></p></div></div><div lang="EN-US" link="blue" vlink="purple" class="gmail_msg"><div class="m_-7130726274844933975WordSection1 gmail_msg">
<p class="MsoNormal gmail_msg"><u class="gmail_msg"></u> <u class="gmail_msg"></u></p>
<p class="MsoNormal gmail_msg"><span style="font-size:10.0pt;font-family:"Arial",sans-serif" class="gmail_msg">Hi Bryan,</span><br class="gmail_msg">
<br class="gmail_msg">
<span style="font-size:10.0pt;font-family:"Arial",sans-serif" class="gmail_msg">Making sure Malahal's reply was received by the user group.</span><br class="gmail_msg">
<br class="gmail_msg">
<span style="font-size:10.0pt;font-family:"Arial",sans-serif" class="gmail_msg">>> Then we noticed that the CES host had 5.4 million files open<br class="gmail_msg">
<br class="gmail_msg">
This is technically not possible with ganesha alone. A process can only open 1 million files on RHEL distro. Either we have leaks in kernel or some other processes contributing to this.<br class="gmail_msg">
<br class="gmail_msg">
Ganesha does keep NFSv3 files open and keep open for performance. It doesn't have a good logic to close them after some inactivity. It does close them if the number is close to max open files which is configurable.<br class="gmail_msg">
<br class="gmail_msg">
PS: kNFS does open, read/write, and then close. No caching in older versions. They did have a feature in a recent code to cache open files in NFSv3 as well.<br class="gmail_msg">
</span><br class="gmail_msg">
<span style="font-size:10.0pt;font-family:"Arial",sans-serif" class="gmail_msg">Regards, The Spectrum Scale (GPFS) team<br class="gmail_msg">
<br class="gmail_msg">
------------------------------------------------------------------------------------------------------------------<br class="gmail_msg">
If you feel that your question can benefit other users of Spectrum Scale (GPFS), then please post it to the public IBM developerWroks Forum at
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If your query concerns a potential software error in Spectrum Scale (GPFS) and you have an IBM software maintenance contract please contact <a href="tel:(800)%20237-5511" value="+18002375511" class="gmail_msg" target="_blank">1-800-237-5511</a> in the United States or your local IBM Service Center in other countries.
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The forum is informally monitored as time permits and should not be used for priority messages to the Spectrum Scale (GPFS) team.</span><br class="gmail_msg">
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<span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f" class="gmail_msg">From: </span><span style="font-size:7.5pt;font-family:"Arial",sans-serif" class="gmail_msg">Bryan Banister <<a href="mailto:bbanister@jumptrading.com" class="gmail_msg" target="_blank">bbanister@jumptrading.com</a>></span><br class="gmail_msg">
<span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f" class="gmail_msg">To: </span><span style="font-size:7.5pt;font-family:"Arial",sans-serif" class="gmail_msg">gpfsug main discussion list <<a href="mailto:gpfsug-discuss@spectrumscale.org" class="gmail_msg" target="_blank">gpfsug-discuss@spectrumscale.org</a>></span><br class="gmail_msg">
<span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f" class="gmail_msg">Date: </span><span style="font-size:7.5pt;font-family:"Arial",sans-serif" class="gmail_msg">03/23/2017 08:27 AM</span><br class="gmail_msg">
<span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f" class="gmail_msg">Subject: </span><span style="font-size:7.5pt;font-family:"Arial",sans-serif" class="gmail_msg">Re: [gpfsug-discuss] CES node slow to respond</span><br class="gmail_msg">
<span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f" class="gmail_msg">Sent by: </span><span style="font-size:7.5pt;font-family:"Arial",sans-serif" class="gmail_msg"><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" class="gmail_msg" target="_blank">gpfsug-discuss-bounces@spectrumscale.org</a></span><u class="gmail_msg"></u><u class="gmail_msg"></u></p>
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<br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg"><span style="font-size:10.0pt" class="gmail_msg">Anybody from IBM willing/able to give us some explanation of why ganesha is holding open so many files? Is this expected/needed/etc?</span></tt><span style="font-size:10.0pt;font-family:"Courier New"" class="gmail_msg"><br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg">Or do we have to open a PMR to get some kind of explanation?</tt><br class="gmail_msg">
<tt class="gmail_msg">-B</tt><br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg">-----Original Message-----</tt><br class="gmail_msg">
<tt class="gmail_msg">From: <a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" class="gmail_msg" target="_blank">gpfsug-discuss-bounces@spectrumscale.org</a> [</tt></span><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" class="gmail_msg" target="_blank"><tt class="gmail_msg"><span style="font-size:10.0pt" class="gmail_msg">mailto:gpfsug-discuss-bounces@spectrumscale.org</span></tt></a><tt class="gmail_msg"><span style="font-size:10.0pt" class="gmail_msg">]
On Behalf Of Matt Weil</span></tt><span style="font-size:10.0pt;font-family:"Courier New"" class="gmail_msg"><br class="gmail_msg">
<tt class="gmail_msg">Sent: Thursday, March 23, 2017 10:24 AM</tt><br class="gmail_msg">
<tt class="gmail_msg">To: <a href="mailto:gpfsug-discuss@spectrumscale.org" class="gmail_msg" target="_blank">gpfsug-discuss@spectrumscale.org</a></tt><br class="gmail_msg">
<tt class="gmail_msg">Subject: Re: [gpfsug-discuss] CES node slow to respond</tt><br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg">FYI all</tt><br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg">We also ran into this after bumping maxFilesToCache.</tt><br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg">Mar 22 13:02:37 ces1 ntpd[1191]: ./../lib/isc/unix/ifiter_ioctl.c:348:</tt><br class="gmail_msg">
<tt class="gmail_msg">unexpected error:</tt><br class="gmail_msg">
<tt class="gmail_msg">Mar 22 13:02:37 ces1 ntpd[1191]: making interface scan socket: Too many</tt><br class="gmail_msg">
<tt class="gmail_msg">open files in system</tt><br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg">fix</tt><br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg">sysctl -w fs.file-max=1000000</tt><br class="gmail_msg">
<br class="gmail_msg">
<br class="gmail_msg">
<tt class="gmail_msg">On 3/22/17 12:01 PM, Bryan Banister wrote:</tt><br class="gmail_msg">
<tt class="gmail_msg">> We had a similar issue and also were instructed by IBM Support to increase the maxFilesToCache to an insane value... Basically when the file cache gets full then the host will spend all of its cycles looking for a file to evict every time a new file is
opened... baaaah.</tt><br class="gmail_msg">
<tt class="gmail_msg">></tt><br class="gmail_msg">
<tt class="gmail_msg">> Not sure why Ganesha has to keep so many files open... I can't believe our NFS clients actually keep that many open. cNFS never needed this.</tt><br class="gmail_msg">
<tt class="gmail_msg">> -Bryan</tt><br class="gmail_msg">
<tt class="gmail_msg">></tt><br class="gmail_msg">
<tt class="gmail_msg">> -----Original Message-----</tt><br class="gmail_msg">
<tt class="gmail_msg">> From: <a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" class="gmail_msg" target="_blank">gpfsug-discuss-bounces@spectrumscale.org</a> [</tt></span><a href="mailto:gpfsug-discuss-bounces@spectrumscale.org" class="gmail_msg" target="_blank"><tt class="gmail_msg"><span style="font-size:10.0pt" class="gmail_msg">mailto:gpfsug-discuss-bounces@spectrumscale.org</span></tt></a><tt class="gmail_msg"><span style="font-size:10.0pt" class="gmail_msg">]
On Behalf Of Matt Weil</span></tt><span style="font-size:10.0pt;font-family:"Courier New"" class="gmail_msg"><br class="gmail_msg">
<tt class="gmail_msg">> Sent: Wednesday, March 22, 2017 11:43 AM</tt><br class="gmail_msg">
<tt class="gmail_msg">> To: gpfsug main discussion list <<a href="mailto:gpfsug-discuss@spectrumscale.org" class="gmail_msg" target="_blank">gpfsug-discuss@spectrumscale.org</a>></tt><br class="gmail_msg">
<tt class="gmail_msg">> Subject: [gpfsug-discuss] CES node slow to respond</tt><br class="gmail_msg">
<tt class="gmail_msg">></tt><br class="gmail_msg">
<tt class="gmail_msg">> All,</tt><br class="gmail_msg">
<tt class="gmail_msg">></tt><br class="gmail_msg">
<tt class="gmail_msg">> We had an indecent yesterday where one of our CES nodes slowed to a</tt><br class="gmail_msg">
<tt class="gmail_msg">> crawl. GPFS waiters showed pre fetch threads going after inodes.</tt><br class="gmail_msg">
<tt class="gmail_msg">> iohist also showed lots of inode fetching. Then we noticed that the CES</tt><br class="gmail_msg">
<tt class="gmail_msg">> host had 5.4 million files open.</tt><br class="gmail_msg">
<tt class="gmail_msg">></tt><br class="gmail_msg">
<tt class="gmail_msg">> The change I made was to set maxStatCache=DEFAULT because it is linux.</tt><br class="gmail_msg">
<tt class="gmail_msg">> And set maxFilesToCache=10000000 it was set to 500000. Then restarted GPFS.</tt><br class="gmail_msg">
<tt class="gmail_msg">></tt><br class="gmail_msg">
<tt class="gmail_msg">> Is there something else we should change as well.</tt><br class="gmail_msg">
<tt class="gmail_msg">></tt><br class="gmail_msg">
<tt class="gmail_msg">> Thanks</tt><br class="gmail_msg">
<tt class="gmail_msg">></tt><br class="gmail_msg">
<tt class="gmail_msg">> Matt</tt><br class="gmail_msg">
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